Inflatable balloon



FIG. 1 is a front perspective view of the inflatable balloon showing mynew design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof, the rear being the same;

FIG. 4 is a left side elevational view, the right side being the same;and,

FIG. 5 is a bottom plan view thereof.

The ornamental design for an inflatable balloon, as shown and described.